Plasma Physics and Technology Journal
Volume 5 (2018)

Number 1

Low-Voltage Circuit-Breaker Behavior under Overload Conditions

Dostal L., Valenta J., Simek D.

Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 12, 616 00 Brno, Czech Republic

This article deals with temperature-rise of current path of modern low-voltage circuitbreaker with rotary contact system at overloads and subsequent experimental verification of selected model. The first part describes optimal setting of input conditions of simulation and mainly transient phenomena at contacts causing dynamic change of contact resistances due to change of total contact force, a new challenge to be solved in this contribution. The second part devotes laboratory measurement on prepared sample of the breaker for verification of transient simulation. These simulations are not only important for understanding of rotary system behavior under overloads, but forms an essential part of R & D process due to the speed-up of optimal current path design. In the end, both the financial costs and time effort could be decreased.

Keywords: low-voltage circuit-breaker, overload, Holm force, thermal losses, SolidWorks Flow Simulation.

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25 Years of Microplasma Science and Applications:
A Status Report

Becker K. H.

New York University Tandon School of Engineering, Brooklyn, NY 11201, USA

Microplasmas gained recognition as a distinct area of research within the larger field of plasma science about 25 years ago. Since then, the activity in microplasma research and applications has continuously increased. This paper provides a summary of some of the pertinent developments of microplasma sources that have contributed to making this field an exciting and rapidly growing area of interest, both in terms of scientific challenges and technological opportunities.

Keywords: microplasma, discharge, plasma, microhollow cathode.

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Fast tracking abstracts for volume 5, number 1.

Number 2

Simulation of Arc Motion in Alternating Magnetic Field Using Dimensionless Momentum Equation

Takeda K., Akiho R.

Faculty of Systems Science and Technology, Akita Prefectural University, Yuri-Honjyo, Akita, 015-0055, Japan

A new heat-treatment system has been developed using an arc driven by an alternating magnetic field. The arc motion was theoretically investigated by the method of non-dimensional analysis. After the definition of the pertinent characteristic length and time, the momentum equation was converted into the dimensionless form. This approach gave us not only a short cut to simulate the arc motion but also clear understanding on the nature of the magnetically driven arc.

Keywords: heat treatment, arc motion, magnetic field, momentum equation, non-dimensional analysis.

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Fast tracking abstracts for volume 5, number 2.

Number 3

Rayleigh-Taylor Instability with Finite Skin Depth

Silveira F. E. M.

Universidade Federal do ABC, Rua Santa Ad\'elia, 166, Bairro Bangu, 09210-170, Santo Andre, SP, Brazil

In this work, the Rayleigh-Taylor instability is addressed in a viscous-resistive current slab, by assuming a finite electron skin depth. The formulation is developed on the basis of an extended form of Ohm's law, which includes a term proportional to the explicit time derivative of the current density. In the neighborhood of the rational surface, a viscous-resistive boundary-layer is defined in terms of a resistive and a viscous boundary-layers. As expected, when viscous effects are negligible, it is shown that the viscous-resistive boundary-layer is given by the resistive boundary-layer. However, when viscous effects become important, it is found that the viscous-resistive boundary-layer is given by the geometric mean of the resistive and viscous boundary-layers. Scaling laws of the time growth rate of the Rayleigh-Taylor instability with the plasma resistivity, fluid viscosity, and electron number density are discussed.

Keywords: resistive instabilities, inertial effects, boundary-layers, scaling laws

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Investigation of Peculiarities of the Discharge Excitation with Hollow Cathode Effect in N2 in a Tube Electrode

Bordusau S., Bozhko A., Madveika S., Tsikhan O., Barouski I.

Belarusian State University of Informatics and Radioelectronics, P.Brovki 6, 220013 Minsk, Belarus

The influence of some constructive discharge system elements on the electric excitation modes and stable maintaining of pulse glow discharge plasma in N2 in a hollow tube cathode has been investigated. The following discharge system changes have been performed: the position of a hollow electrode-cathode in the dielectric tube-holder; the method of plasma forming gas feeding to the discharge area; the distance between the electrode-cathode and counter-electrode (grounded anode). The investigation has been carried out within 50-700Pa N2 pressure range. The obtained results may be used in the design of gas discharge systems with hollow cathode effect.

Keywords: discharge, hollow cathode, vacuum, tube electrode

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GC-MS and GC-FID analysis of products from glow discharge in N2 + CH4 mixture

Mazanková V.1, Manduchová I.2, Krčma F.2, Prokeš F.3, Trunec D.3

1Faculty of Military Technology, University of Defense, Kounicova 65, 662 10 Brno, Czech Republic
2Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 612 00 Brno, Czech Republic
3Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic

This work extends our previous investigation of nitrogen-methane atmospheric glow discharge for the simulation of chemical processes in prebiotic atmospheres. Beside the volume chemical reactions also heterogeneous chemical reactions on surfaces of solid state bodies can be important. So in presented experiments the electrodes with different shapes and different surface areas were used. Exhaust products of discharge in this gas mixture were analyzed by Gas Chromatography - Mass Spectrometry (GC-MS) and Gas Chromatography - Flame Ionization Detector (GC-FID). The major products identified in chromatograms were hydrogen cyanide and acetylene.

Keywords: prebiotic atmosphere, GC-MS, GC-FID, glow discharge

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Impact of Collective Effects on Plasma Ionization

Djebli M.

Theoretical Physics Laboratory, Faculty of Physic, USTHB BP. 32 Bab-Ezzouar 16079, Algiers, Algeria

Plasma can be produced using different schemes based on ionization processes of a neutral gas. Recently, it was demonstrated that due to collective effects the ionization potential of chemical elements can be changed particularly for dense plasmas. We investigated this characteristic for mono-atomic gases and found that the critical density for which these effects are significant is no ~ 1013 cm-3. The latter depends on atom's ionization energy. It is also found that this effect can only be observed for a certain range of density and temperature related to the first ionization potential of the chemical element.

Keywords: ionization, Saha equation, neutral plasma

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Morphology and wettability of polytetrafluoroethylene-like films deposited onto track-etched membrane surface in vacuum

Kravets L.1, Gainutdinov R.2, Gilman A.3, Yablokov Y.3, Satulu V.4, Mitu B.4, Dinescu G.4

1Joint Institute for Nuclear Research, Flerov Laboratory of Nuclear Reactions, Joliot-Curie 6, 141980 Dubna, Russia
2Shubnikov Institute of Crystallography of FSRC "Crystallography and Photonics", Russian Academy of Sciences, Leninskii pr. 59, 119333 Moscow, Russia
3Enikolopov Institute of Synthetic Polymer Materials, Russian Academy of Science, Profsoyuznaya 70, 117393 Moscow, Russia
4National Institute for Laser, Plasma and Radiation Physics, Atomistilor 409, 077125 Magurele, Bucharest, Romania

The surface morphology and wettability of nanoscale polytetrafluoroethylene-like films deposited onto the surface of the poly(ethylene terephthalate) track-etched membrane by RF-magnetron and electron-beam sputtering of polytetrafluoroethylene in vacuum have been studied. It was shown that the morphology of films formed with the use of these coating techniques varies considerably. This is due to the size of the deposited polymer nanostructures. The nanostructures produced by the electron-beam sputtering of polytetrafluoroethylene are much bigger in size. Investigation of the surface properties of the composite membranes obtained in these processes showns that the deposition of the polytetrafluoroethylene-like film onto track-etched membrane leads to hydrophobization of its surface. The water contact angle for the composite membranes significantly increases.

Keywords: RF-magnetron sputtering of polymer, electron-beam dispersion of polymer, polytetrafluoroethylene, composite membranes

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Silicon in spectroscopic data of world databases

Pokorny J.

Faculty of Electrical Engineering and Communication, BUT, Technicka 3058/10, 616 00 Brno, Czech Republic

This article deals with comparison of three world spectroscopic databases: NIST, Kurucz and Atomic Line List. Our target was to calculate the differences in input data and the ratio of Stark broadening and function F which depends on electron density, temperature and pressure. Stark broadening is one of pressure broadenings of spectral lines which arise from the collisions of the emitters with neighboring particles. Stark broadening is due to charged perturbers. We developed the program NKrov to be able to compare data in databases. There were some differences in the database format and content. Our results could be used in science and technology.

Keywords: NIST database, Kurucz database, ALL database, Stark broadening

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Gas Temperature Distribution of Hydrogen in Cathode Fall Region of Grimm Glow Discharge

Majstorović G.1, Vasiljević M.2, Šišović N.2

1Military Academy, University of Defence, Pavla Jurisica Sturma 33, 11105 Belgrade, Serbia
2Faculty of Physics, University of Belgrade, P.O. Box 44, 11001 Belgrade, Serbia

Optical emission spectroscopy technique was used to measure gas temperature along the axis of cylindrical abnormal glow discharge parallel to the copper cathode surface (side-on) in hydrogen-argon mixture at low pressure. The rotational temperature of excited state of H2 was determined from the rotational structure of Q branch of Fulcher-alpha diagonal bands using Boltzmann plot technique while the obtained ground vibrational state temperature is assumed to be equal to gas temperature. The temperature T0 determined from the rotational population density distribution in an excited vibrational state can be considered as a valid estimation of the ground state temperatutre i.e. H2 gas temperature.

Keywords: spectroscopy, hydrogen molecule, rotational temperature measurement

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Sustainment of high-beta mirror plasma by neutral beams

Akhmetov T. D.1,2, Davydenko V. I.1,2, Ivanov A. A.1,2, Murakhtin S. V.1

1Budker Institute of Nuclear Physics, 11 Acad. Lavrentieva Pr., 630090 Novosibirsk, Russian Federation
2Novosibirsk State University, 2 Pirogova Street, 630090 Novosibirsk, Russian Federation

The report presents two experiments carried out in Budker Institute for obtaining the maximum plasma beta (ratio of the plasma pressure to magnetic field pressure) in axially symmetric magnetic field. The experiments are based on injection of powerful focused neutral beams with high neutral power density in the plasma. The produced fast ion population significantly increases the plasma pressure. It the axially symmetric GDT experiment (Gas Dynamic Trap) the plasma beta exceeded 0.6 at the fast ion turning points. The CAT experiment (Compact Axisymmetric Toroid) is being prepared for obtaining a plasmoid with extremely high diamagnetism in axially symmetric magnetic field. Reversal of magnetic field in the plasmoid is possible in this experiment.

Keywords: axisymmetric mirror, neutral beam injection

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Comparison of copper and graphite crucibles for Si extraction from TiO2 - SiO2 system at plasma-arc heating

Kirpichev D. E., Nikolaev A. A., Nikolaev A. V.

Baikov Institute of Metallurgy & Materials Science (IMET RAS), Leninskiy av. 49, 119334 Moscow, Russian Federation

Plasma arc recovery melting of the quartz-leucoxene concentrate was investigated. Experiments were made in laboratory DC plasma arc furnace in copper and graphite crucibles. The best results were reached in a cold copper crucible. The temperature field of a pool was calculated in hot graphite and cold copper crucibles. It was shown that in graphite crucible diameter of anode spot is more, and material temperature in spot is less, than in copper crucible. This fact was suggested as a reason of the worst refinement in graphite crucible.

Keywords: DC plasma arc, anode spot, reducing, leucoxene, silicon, rutil

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